Variable Speed or Variable Frequency?
Our engineers have been the industry’s trusted advisors on motors for 60 years. Our knowledgeable staff will give you all the tools to choose either driving your motor with variable speed (VSD) or variable frequency (VFD), giving the advantages of each option.
- Can be designed and manufactured to meet a variety of demanding application conditions
- Many variations of open drip proof, totally enclosed liquid-cooled and blower-cooled motors are available
- Various motor winding protection and insulation classes may also be used in severe conditions
- The options are available for all frame sizes up to 500T
Open Drip Proof (ODP)
- External air circulated through motor for cooling
- Must protect from liquid or solid particles (1.97in diameter)
- Enclosure must protect from contact with internal parts
- Enclosure can handle some moisture and contamination
- Suitable for general industry with relatively clean environments
Weather Protected Types I and II (WPI, WPII)
- Open motor with small amount of additional protect from rain, snow and other airborne particles
- Screens over openings with max allowance of a ¾” rod
- Prevent entrance of water and particles up to 15° from vertical
- WPII requires minimum three 90° direction changes in intake air
- Lowers intake air speed to 600 fps and allows foreign particles to drop out of air stream
Totally Enclosed fan cooled (TEFC)
- Enclosed to prevent the free exchange of air between the inside and outside of enclosure
- Usually a finned frame to optimize cooling effect
- Exterior surface is cooled by an external fan attached to the motor shaft
- Motor cooling is dependent on speed
- Suitable for harsh and corrosive environments such as mines, oil & gas and waste water treatment areas
Inverter Duty Motor:
An inverter-duty motor may need to be an option, if the motors are to be driven by a VFD. If the motor overheats, the motor’s life will be reduced. Therefore, there are minimum speed requirements for all motors. Inverter-duty motors are designed to not overheat and are capable of withstanding higher voltage spikes without their insulation failing.
An inverter duty motor:
- Has increased insulation
- Has ventilation fans
- Has more winding cross-sections to deal with heat
- Can operate at load with speeds below synchronism, within the name plates rating.
Our technical support can determine if an inverter-duty motor is required for your application.
Specialty High Speed Motor:
Many of today’s high-performance test stand or dynamometer applications require speeds exceeding 20,000 RPM. Dynamatic® designs accommodate pressurized lubrication systems, special bearings and precision balancing which provide continuous operation at these high speeds. A trunnion mounted motor (with a load cell) or foot mounted motor (with an in-line-shaft torque transducer) may be used to indicate the developed torque.